Marvin / Pella energy efficient windows
We are considering replacing original (50 yr old) windows in our home due to the tax credit. We've narrowed it down to Marvin Ultimates or Pella Architect series. However, in order to qualify for the tax credit, the windows need a specific glass - the Marvins need LoE366 and the Pellas need LoE2 (or dual loE). The glass sample for the Pellas seemed darker than the sample for the Marvins. Both companies claim to use Cardinal as their manufacturer. Is there a difference in the glass? Our home is a bit dark so I'm hesitant to use a darker glass. Any thoughts or suggestions, or other options we should look at? Thanks!